package com.atguigu.gulimall.seckill.service.impl;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.atguigu.common.to.mq.SeckillOrderTo;
import com.atguigu.common.utils.R;
import com.atguigu.common.vo.MemberEntity;
import com.atguigu.gulimall.seckill.feign.CouponFeignService;
import com.atguigu.gulimall.seckill.feign.ProductFeignService;
import com.atguigu.gulimall.seckill.interceptor.LoginUserInterceptor;
import com.atguigu.gulimall.seckill.service.SeckillService;
import com.atguigu.gulimall.seckill.to.SeckillSkuRedisTo;
import com.atguigu.gulimall.seckill.vo.SeckillSessionWithSkus;
import com.atguigu.gulimall.seckill.vo.SeckillSkuVo;
import com.atguigu.gulimall.seckill.vo.SkuInfoVo;
import com.baomidou.mybatisplus.core.toolkit.IdWorker;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.redisson.api.RSemaphore;
import org.redisson.api.RedissonClient;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.BoundHashOperations;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.xml.crypto.Data;
import java.math.BigDecimal;
import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

/**
 * @Author: WackyBoy
 * @Date: 2021/7/17 21:19
 */

@Slf4j
@Service
public class SeckillServiceImpl implements SeckillService {

    @Autowired
    CouponFeignService couponFeignService;

    @Autowired
    StringRedisTemplate redisTemplate;

    @Autowired
    ProductFeignService productFeignService;

    @Autowired
    RedissonClient redissonClient;

    @Autowired
    RabbitTemplate rabbitTemplate;

    private final String SESSIONS_CACHE_PREFIX = "seckill:sessions:";

    private final String SKUKILL_CACHE_PREFIX = "seckill:skus:";

    private final String SKU_STOCK_SEMAPHORE = "seckill:stock:"; // + 商品随机码



    @Override
    public void uploadSeckillSkuLatest3Days() {
        // 扫描最近三天需要参与秒杀的活动
        R session = couponFeignService.getLatest3DaySession();
        if(session.getCode() == 0) {
            // 上架商品
            List<SeckillSessionWithSkus> sessionData = session.getData(new TypeReference<List<SeckillSessionWithSkus>>() {
            });
            // 缓存到redis
            // 1. 缓存活动信息
            saveSessionInfos(sessionData);
            // 2. 保存活动的关联商品信息
            saveSessionSkuInfos(sessionData);
        }

    }

    /**
     * 获取当前可以参与秒杀的商品信息
     * @return
     */
    @Override
    public List<SeckillSkuRedisTo> getCurrentSeckillSkus() {
        // 1. 确定当前时间属于哪个秒杀场次
        long time = new Date().getTime();
        Set<String> keys = redisTemplate.keys(SESSIONS_CACHE_PREFIX + "*");
        for (String key : keys) {
            String replace = key.replace(SESSIONS_CACHE_PREFIX, "");
            String[] s = replace.split("_");
            Long start = Long.parseLong(s[0]);
            Long end = Long.parseLong(s[1]);
            if(time >= start && time <= end) {
                // 2. 获取这个秒杀场次需要的所有商品信息
                List<String> range = redisTemplate.opsForList().range(key, -100, 100);
                BoundHashOperations<String, String, String> hashOps = redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);
                List<String> list = hashOps.multiGet(range);
                if(list != null) {
                    List<SeckillSkuRedisTo> collect = list.stream().map(item -> {
                        SeckillSkuRedisTo redis = JSON.parseObject((String) item, SeckillSkuRedisTo.class);
//                        redis.setRandomCode(null);
                        return redis;
                    }).collect(Collectors.toList());
                    return collect;
                }
                break;
            }
        }


        return null;
    }

    @Override
    public SeckillSkuRedisTo getSkuSeckillInfo(Long skuId) {
        // 1. 找到所有需要参与秒杀的商品的key
        BoundHashOperations<String, String, String> hashOps = redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);
        Set<String> keys = hashOps.keys();
        if(keys != null && keys.size() > 0) {
            String regx = "\\d_" + skuId;
            for (String key : keys) {
                if(Pattern.matches(regx, key)) {
                    String json = hashOps.get(key);
                    SeckillSkuRedisTo skuRedisTo = JSON.parseObject(json, SeckillSkuRedisTo.class);
                    // 处理随机码
                    long current = new Date().getTime();
                    if(current >= skuRedisTo.getStartTime() && current <= skuRedisTo.getEndTime()) {

                    } else {
                        skuRedisTo.setRandomCode(null);
                    }
                    return skuRedisTo;
                }
            }
        }
        return null;

    }

    /**
     * TODO: 上架秒杀商品的时候, 每一个数据都有过期时间
     * TODO: 秒杀后续的流程, 简化了收货地址等信息的计算
     * 秒杀的业务处理
     * @param killId
     * @param key
     * @param num
     * @return
     */
    @Transactional
    @Override
    public String kill(String killId, String key, Integer num) {

        long s1 = System.currentTimeMillis();
        MemberEntity respVo = LoginUserInterceptor.loginUser.get();

        // 1. 获取当前秒杀商品的详细信息
        BoundHashOperations<String, String, String> hashOps = redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);
        String json = hashOps.get(killId);
        if(StringUtils.isEmpty(json)) {
            return null;
        } else {
            SeckillSkuRedisTo redis = JSON.parseObject(json, SeckillSkuRedisTo.class);
            // 1. 校验合法性
            Long startTime = redis.getStartTime();
            Long endTime = redis.getEndTime();
            long time = new Date().getTime();
            long ttl = endTime - startTime;
            if(time >= startTime && time <= endTime) {
                // 2. 校验随机码和商品id
                String randomCode = redis.getRandomCode();
                String skuId = redis.getPromotionSessionId() + "_" + redis.getSkuId();
                if(randomCode.equals(key) && killId.equals(skuId)) {
                    // 3. 验证购物的数量是否合理
                    if(num <= redis.getSeckillLimit()) {
                        // 4. 验证是否已经买过: 幂等性: 只要秒杀成功, 就去占位. userID_Sessionid_skuId
                        // TODO: SETNX
                        String redisKey = respVo.getId() + "_" + skuId;
                        // 自动过期
                        Boolean aBoolean = redisTemplate.opsForValue().setIfAbsent(redisKey, num.toString(), ttl, TimeUnit.MILLISECONDS);
                        if(aBoolean) {
                            // 占位成功, 说明没买过
                            RSemaphore semaphore = redissonClient.getSemaphore(SKU_STOCK_SEMAPHORE + randomCode);
                            try {
                                boolean b = semaphore.tryAcquire(num, 100, TimeUnit.MILLISECONDS);
                                if(b) {
                                    // 秒杀成功
                                    // 快速下单, 发送MQ消息 10ms
                                    String timeId = IdWorker.getTimeId();
                                    SeckillOrderTo orderTo = new SeckillOrderTo();
                                    orderTo.setOrderSn(timeId);
                                    orderTo.setMemberId(respVo.getId());
                                    orderTo.setNum(num);
                                    orderTo.setPromotionSessionId(redis.getPromotionSessionId());
                                    orderTo.setSkuId(redis.getSkuId());
                                    orderTo.setSeckillPrice(redis.getSeckillPrice());
                                    rabbitTemplate.convertAndSend("order-event-exchange", "order.seckill.order", orderTo);
                                    long s2 = System.currentTimeMillis();
                                    log.info("耗时...", (s2 - s1));
                                    return timeId;
                                }
                                return null;

                            } catch (InterruptedException e) {
                                e.printStackTrace();
                                return null;
                            }

                        } else {
                            return null;
                        }
                    }
                } else {

                }
            } else {
                return null;
            }
        }
        return null;


    }

    private void saveSessionInfos(List<SeckillSessionWithSkus> sessions) {
        sessions.stream().forEach(session -> {
            Long startTime = session.getStartTime().getTime();
            Long endTime = session.getEndTime().getTime();
            String key = SESSIONS_CACHE_PREFIX + startTime + "_" + endTime;
            // TODO: 锁的粒度有点大, 应该配合ID加锁, 使用set的坏处
            Boolean hasKey = redisTemplate.hasKey(key);
            // 缓存活动信息
            if(!hasKey) {
                List<String> collect = session.getRelationSkus().stream().map(item -> item.getPromotionSessionId() + "_" + item.getSkuId().toString()).collect(Collectors.toList());
                redisTemplate.opsForList().leftPushAll(key, collect);
            }

        });
    }


    private void saveSessionSkuInfos(List<SeckillSessionWithSkus> sessions) {
        sessions.stream().forEach(session -> {
            // 准备hash操作
            // TODO: 避免循环远程调用
            BoundHashOperations<String, Object, Object> ops = redisTemplate.boundHashOps(SKUKILL_CACHE_PREFIX);
            session.getRelationSkus().stream().forEach(seckillSkuVo -> {
                if(!ops.hasKey(seckillSkuVo.getPromotionSessionId().toString() + "_" + seckillSkuVo.getSkuId().toString())) {
                    // 缓存商品信息
                    SeckillSkuRedisTo redisTo = new SeckillSkuRedisTo();
                    // 1. sku的基本数据
                    R skuInfo = productFeignService.getSkuInfo(seckillSkuVo.getSkuId());
                    if(skuInfo.getCode() == 0) {
                        SkuInfoVo info = skuInfo.getData("skuInfo", new TypeReference<SkuInfoVo>(){});
                        redisTo.setSkuInfo(info);
                    }

                    // 2. sku的秒杀信息
                    BeanUtils.copyProperties(seckillSkuVo, redisTo);

                    // 3. 设置上当前商品 的秒杀时间信息
                    redisTo.setStartTime(session.getStartTime().getTime());
                    redisTo.setEndTime(session.getEndTime().getTime());

                    // 4. 随机码
                    String token = UUID.randomUUID().toString().replace("-", "");
                    redisTo.setRandomCode(token);

                    // 如果当前这个场次的商品库存信息已经上架, 就不需要再上架了
                    // 5. 信号量的一大作用: 限流
                    RSemaphore semaphore = redissonClient.getSemaphore(SKU_STOCK_SEMAPHORE + token);
                    // 商品可以秒杀的数量, 作为信号量
                    semaphore.trySetPermits(seckillSkuVo.getSeckillCount());

                    String jsonString = JSON.toJSONString(redisTo);
                    ops.put(seckillSkuVo.getPromotionSessionId().toString()+ "_" + seckillSkuVo.getSkuId().toString(), jsonString);

                }

            });
        });
    }















}
